Memory Model for a Layout Engine and Scripting Engine

ABSTRACT

Various embodiments provide an interface between a Web browser&#39;s layout engine and a scripting engine. The interface enables objects from the layout engine to be recognized by a memory manager in the scripting engine and interact in a streamlined, efficient manner. In accordance with one or more embodiments, the interface allows browser layout engine objects to be created as objects that are native to the scripting engine. Alternately or additionally, in some embodiments, the native objects are further configured to proxy functionality between the layout engine and the scripting engine.

RELATED APPLICATIONS

This is a continuation of and claims priority to U.S. patent applicationSer. No. 13/150,877 filed on Jun. 1, 2011, which is a continuation ofU.S. patent application Ser. No. 13/114,924 filed on May 24, 2011, thedisclosures of which are incorporated by reference herein.

BACKGROUND

Over time, Web pages have evolved to include complex operations that canalter and/or modify a document being rendered in a host environment. Inorder to achieve some of these complex operations, Web programmers canutilize scripting languages to work within the host environment and withthe document being rendered. Many host environments distinguish betweena layout engine, which facilitates the rendering of a document, and ascripting engine, which executes script included in an associated Webpage. Scripts running in the scripting engine can be designed to accessnot only the document being rendered in the layout engine, but objectsand/or elements within the document. In some cases, when a layout enginesupports standardized document access, such as a Document Object Model(DOM), a Web programmer can write a script to manipulate a document andits elements based upon this model.

A layout engine and a scripting engine provide different functionalityfrom one another and, as such, they typically reside, on some level, inseparate modules. This can range from a simple logical separation to amore complex separation between software and/or hardware components.More often, these engines reside in separate and/or associated softwaremodules that communicate with one another. One benefit of thisseparation is that it enables a layout engine to more easily supportmultiple scripting engines. However, since the layout engine isseparated, on some level, from a scripting engine, communicationmechanisms between the modules oftentimes limit what can be exposedbetween the modules, can adversely affect runtime performance, and canintroduce unintended memory management issues.

SUMMARY

This Summary is provided to introduce a selection of concepts in asimplified form that are further described below in the DetailedDescription. This Summary is not intended to identify key features oressential features of the claimed subject matter, nor is it intended tobe used to limit the scope of the claimed subject matter.

Various embodiments provide an interface between a Web browser's layoutengine and a scripting engine. The interface enables objects from thelayout engine to be recognized by a memory manager in the scriptingengine and interact with the scripting engine in a streamlined,efficient manner. In accordance with one or more embodiments, theinterface allows browser objects to be created as objects that arenative to the scripting engine. Alternately or additionally, in someembodiments, the native objects are further configured to proxyfunctionality between the layout engine and the scripting engine.

In some embodiments, binding between the Web browser's layout engine andthe scripting engine can include features configured to enable unifiedprogramming access between the layout engine and the scripting engine.The features can be configured to enhance memory management, enabledirect access between the layout engine and scripting engine, and/orenable mutability of a dual nature object.

Various embodiments can also provide a security model that enablessecure interactions between scripting engines residing in separatedomains. In some cases, protections can be employed to prevent objectaccess and/or restrict access to type system information. Alternately oradditionally, functions that include cross-domain access functionalitycan be marked as safe. In some embodiments, a sub-window proxy canprovide secure transactions across multiple domains to one or moresub-objects associated with a window.

BRIEF DESCRIPTION OF THE DRAWINGS

The same numbers are used throughout the drawings to reference likefeatures.

FIG. 1 illustrates an operating environment in which various principlesdescribed herein can be employed in accordance with one or moreembodiments.

FIG. 2 illustrates a relationship diagram in accordance with one or moreembodiments.

FIG. 3 is a flow diagram that describes steps in a method in accordancewith one or more embodiments.

FIG. 4 illustrates object relationships in a memory model in accordancewith one or more embodiments.

FIG. 5 illustrates an example data structure in accordance with one ormore embodiments.

FIG. 6 illustrates example data structures in accordance with one ormore embodiments.

FIG. 7 is a flow diagram that describes steps in a method in accordancewith one or more embodiments.

FIG. 8 illustrates an example binding module in accordance with one ormore embodiments.

FIG. 9 is a flow diagram that describes steps in a method in accordancewith one or more embodiments.

FIG. 10 illustrates a relationship diagram in accordance with one ormore embodiments.

FIG. 11 is a flow diagram that describes steps in a method in accordancewith one or more embodiments.

FIG. 12 is a flow diagram that describes steps in a method in accordancewith one or more embodiments.

FIG. 13 is a flow diagram that describes steps in a method in accordancewith one or more embodiments.

FIG. 14 is a flow diagram that describes steps in a method in accordancewith one or more embodiments

FIG. 15 illustrates a process diagram in accordance with one or moreembodiments.

FIG. 16 is a flow diagram that describes steps in a method in accordancewith one or more embodiments.

FIG. 17 illustrates an example security module in accordance with one ormore embodiments.

FIG. 18 is a flow diagram that describes steps in a method in accordancewith one or more embodiments.

FIG. 19 illustrates a relationship diagram in accordance with one ormore embodiments.

FIG. 20 illustrates an example extended IDL file in accordance with oneor more embodiments.

FIG. 21 is a flow diagram that describes steps in a method in accordancewith one or more embodiments.

FIG. 22 illustrates an example system that can be utilized to implementone or more embodiments.

DETAILED DESCRIPTION Overview

Various embodiments provide an interface between a Web browser's layoutengine and a scripting engine. Typically, as an overview to an exampleprocess, a user will open a Web browser and navigate to a Web page. TheWeb page can be configured to determine what version of the Web browseris running, such as what features are supported. At some point while theWeb page is being rendered, a scripting engine can be created, such asthrough a dynamic request for functionality (e.g. IDispatchEx), orthrough a script being parsed. In some embodiments, creation and/orinitialization of the scripting engine can include registering a typesystem, establishing various relationships between the scripting engineand the Web browser's layout engine, as well as constructing bindingsthat are associated with the various relationships, as will be describedbelow in detail. In some cases, the user may navigate to a second Webpage. Upon transitioning to the second Web page, the Web browser can beconfigured to create a new scripting engine associated with the secondpage, transfer objects from the first scripting engine to the newscripting engine, and then close the first scripting engine.

The interface and bindings enable various objects from the layout engineto be recognized by a memory manager in the scripting engine andinteract with the scripting engine in a streamlined, efficient manner.In accordance with one or more embodiments, the interface allows browserobjects to be created as objects that are native to the scriptingengine. Alternately or additionally, in some embodiments, the nativeobjects are further configured to proxy functionality between the layoutengine and the scripting engine.

In some embodiments, binding between the Web browser's layout engine andthe scripting engine can include features configured to enable unifiedprogramming access between the layout engine and the scripting engine.The features can be configured to enhance memory management, enabledirect access between the layout engine and scripting engine, and/orenable mutability of a dual nature object.

Various embodiments can also provide a security model that enablessecure interactions between scripting engines residing in separatedomains. In some cases, protections can be employed to prevent objectaccess and/or restrict access to type system information. Alternately oradditionally, functions that include cross-domain access functionalitycan be marked as safe. In some embodiments, a sub-window proxy canprovide secure transactions across multiple domains to one or moresub-objects associated with a window.

In one or more embodiments, extensions to an Interface DefinitionLanguage (IDL) can enable direct integration of a layout engine and ascripting engine. In some embodiments, the extended IDL can enablegeneration of code configured to bridge the layout engine and scriptingengine. Alternately or additionally, hierarchical relationships betweenobjects and their associated APIs can be described using the extendedIDL. In some embodiments, the extended IDL can include syntax todescribe attributes of the objects and/or the associated APIs.

In the discussion that follows, a section entitled “OperatingEnvironment” is provided and describes one environment in which one ormore embodiments can be employed. Following this, a section entitled“Object Integration and Memory Model” describes an architecture thatenables objects from a Web browser's layout engine to be recognized by amemory manager in a scripting engine, and further enables streamlinedinteractions between the engines. After this, a section entitled “DirectSystem Integration” describes provided features that enable directsystem integration between a layout engine and a scripting engine. Next,a section entitled “Security Model” describes how security can beenforced in accordance with one or more embodiments. Following this, asection entitled “Interface Definition Language Integration” describeshow an interface definition language can be extended to define ahierarchy of objects and their associated APIs and/or attributes. Afterthis, a section entitled “Other Considerations” describes additionalconsiderations and/or features. Last, a section entitled “ExampleSystem” describes an example system that can be utilized to implementone or more embodiments.

Having provided an overview of various embodiments that are to bedescribed below, consider now an example operating environment in whichone or more embodiments can be implemented.

Operating Environment

FIG. 1 illustrates an operating environment in accordance with one ormore embodiments, generally at 100. Environment 100 includes a computingdevice 102 having one or more processors 104, one or morecomputer-readable storage media 106 and one or more applications 108that reside on the computer-readable storage media and which areexecutable by the processor(s). The computer-readable storage media caninclude, by way of example and not limitation, all forms of volatile andnon-volatile memory and/or storage media that are typically associatedwith a computing device. Such media can include ROM, RAM, flash memory,hard disk, removable media and the like. One specific example of acomputing device is shown and described below in FIG. 21.

In addition, computing device 102 includes a software application in theform of a Web browser 110. Any suitable Web browser can be used examplesof which are available from the assignee of this document and others.Browser 110 can include or utilize separate modules in itsfunctionality, such as layout engine 112 and scripting engine(s) 114.Layout engine 112 includes functionality that can, among other things,process marked up content (such as HTML, XML, image files, etc.) andformatting information (such as CSS, XSL, etc.) to render and/or displayformatted content. Scripting engine(s) 114 include functionality thatcan process and execute scripting language code. While illustrated asbeing incorporated into browser 110, it is to be appreciated andunderstood that scripting engine(s) 114 can be implemented as standalonecomponents. Alternately or additionally, scripting engine(s) 114 can beimplemented as part of applications 108 and/or part of the system'soperating system.

Computing device 102 also includes a binding module 116, which includesfunctionality that enables layout engine 112 and scripting engine 114 tobind, interface, and/or communicate with one another, as described inmore detail below.

In addition, computing device 102 also includes a security module 118,which includes functionality that enables cross-domain security to beenforced with scripting engine 114 and/or layout engine 112, as well asfor efficiencies to be enhanced for same-origin requests, as describedbelow. In some embodiments, security module 118 includes features and/orfunctionality incorporated into and/or utilized by layout engine 112and/or scripting engine 114, as further described below.

In one or more embodiments, computing device 102 also includes one ormore extended Interface Definition Language (IDL) files 120. An extendedIDL file 120 can include various extensions to an IDL that enablefurther description and/or definition for objects and their associatedApplication Programming Interfaces (APIs), as further described below.

In addition, environment 100 includes a network 122, such as theInternet, and one or more Web sites 124 from and to which content can bereceived and sent. Such content can include any type of content that istypically received and processed by browser 110.

Computing device 102 can be embodied as any suitable computing devicesuch as, by way of example and not limitation, a desktop computer, aportable computer, a handheld computer such as a personal digitalassistant (PDA), cell phone, and the like.

Having described an example operating environment, consider now adiscussion of object integration and a memory model that enables a Webbrowser's layout engine to interface with one or more scripting enginesin an efficient and streamlined manner.

Object Integration and Memory Model

In accordance with one or more embodiments, an interface between a Webbrowser's layout engine and scripting engine enables objects from thelayout engine to be integrated into the scripting engine memory space.For example, in some embodiments, objects native to the scripting enginememory space can be bound to objects associated with the layout enginememory space. To access the layout engine objects, the scripting enginecan access the objects native to scripting engine memory space. Thenative objects can be further configured to proxy functionality betweenthe layout engine and the scripting engine.

As an example, consider FIG. 2, which illustrates relationship blockdiagram 200 depicting a relationship between a scripting engine (thescripting engine side) and a layout engine (the layout engine side) inaccordance with one or more embodiments. The scripting engine sideincludes three functional blocks: user code (script program) 202,dynamic properties 204 and JavaScript Type System 206. The layout engineside includes two functional blocks: document management code 208,illustrated here as Document Object Model (DOM) code, and attributestorage (elements) 210. While this example illustrates the scriptingengine as a JavaScript engine and the layout engine as including a DOMas its standardized document access, it is to be appreciated andunderstood that any type of script language and/or standardized documentaccess could be utilized without departing from the spirit of theclaimed subject matter.

In the illustrated and described embodiment, one or more trampolines 212are logically interposed between the scripting engine and the layoutengine. As will become apparent below, the trampoline serves to enablethe scripting engine and layout engine to communicate and callfunctionality between each other.

In the illustrated and described embodiment, user script code 202comprises script code that can be interpreted and executed by thescripting engine, as will be appreciated by the skilled artisan. In someembodiments, user script code 202 can include script code from Webpages. Among other things, user script code 202 can include script thatenables interaction with a host environment rendering a particular Webpage. Script code can be embedded in or included from HTML pages and caninteract with the DOM of the Web page. Typical, simple uses of scriptcode include, by way of example and not limitation, opening or poppingup a new window with programmatic control over size, position andattributes; validating input values of a Web form to ensure that thevalues are acceptable before being submitted to a server; and changingimages as the mouse cursor moves over them.

Dynamic properties 204 enable an ability to set and/or change propertiesof objects associated with the scripting language and/or scriptingengine dynamically. In addition to setting and/or changing properties ofscripting language objects, dynamic properties 204 include the abilityto dynamically set and/or change properties associated with objects inthe layout engine, such as, by way of example and not limitation,various DOM objects included in and/or associated with document objectmanagement code 208. Alternately or additionally, dynamic properties 204can include properties, prototypes, and/or objects created throughexecution of user code 202. It should be noted that dynamic properties204, regardless of their associated object(s), can be stored entirely inmemory that is managed through the scripting engine.

In one or more embodiments, type system 206 is configured to associate atype with an object and/or value such that the value and/or object canbe properly accessed. For example, a type system can ensure that acorrect prototype is used for the object and/or value. Alternately oradditionally, type system 206 can be configured to dynamically typeobjects and/or values. In some embodiments, type system 206 can includetype system information associated with one or more objects in documentobject management code 208.

On the layout engine side, document management code 208 includesfunctionality that enables the layout engine to create, manage, and/orrender documents. Document management code 208 can also enable externalexposure and/or access of or to document(s). For example, a Web page caninclude user script code that, when running in a scripting engine, canuse the external access of a document to program interactive featuresonto the document. In the illustrated and described embodiment, dynamicproperties 204 include dynamic properties of document management code208 and are stored in the scripting engine memory space. Conversely,attributes storage 210, as illustrated here, utilizes layout enginememory space. Attributes storage 210 can include static attributesand/or elements associated with document management code 208.

In one or more embodiments, trampoline(s) 212, logically interposedbetween the scripting engine side and the layout engine side, representsat least one bridge between the scripting engine and the layout engine.As illustrated, trampoline 212 can be logically positioned between thescripting engine and the layout engine and, in at least someembodiments, can be configured redirect a call from an object in thescripting engine memory space into a related object in the layout enginememory space, as further discussed below. Thus, the trampoline serves asa redirection mechanism in which the scripting engine can directly calla function associated with an object native to the scripting engine, yethave the call redirected to the layout engine for actual workloadexecution. Such a redirection mechanism enables the two engines tocommunicate without the need to request interface pointers,identification values, and the like. Accordingly, the scripting engineand the layout engine can now be more tightly bound and have a widerrange of access to cross-engine objects.

As an example, consider FIG. 3, which illustrates a flow diagram thatdescribes steps in a method in accordance with one or more embodiments.The method can be performed by any suitable hardware, software,firmware, or combination thereof. In at least some embodiments, aspectsof the method are performed by a system, such as the system illustratedin FIGS. 1 and 2.

Step 300 creates at least one trampoline function. The trampolinefunction can be created in any suitable way, such as through C++ sourceand header files, as further described in a section entitled “InterfaceDefinition Language Integration” below. Step 302 logically interposesthe trampoline function between a scripting engine and a layout engine.Interposing the trampoline function between the two engines enables anability to call functionality across the engines. Using the trampolinefunction, step 304 enables direct access between the scripting engineand the layout engine. For instance, the trampoline function can beconfigured to enable calls from the scripting engine to be redirected asappropriate to the layout engine, as further described above and belowin a section entitled “Dynamic Type System Direct Functions”.

Having described a relationship between a scripting engine, a layoutengine, and trampoline functions, consider now FIG. 4, which illustratesobject relationships in a memory model that includes scripting enginememory space (designated “JavaScript”) and layout engine memory space(designated “COM” to represent a Component Object Model (COM) basedlayout engine).

The layout engine memory space includes a variety of objects, includinga CBase object 402 that represents a COM based object with relationshipsto other objects, such as CBase object 404, Internal Layout Engineobject 406 and ActiveX/BHO object 408 (where “BHO” stands for “BrowserHelper Object”).

The scripting engine memory space includes a variety of objects, such asroot object 410, object graph object 412, and var objects 414, 416. Rootobject 410 represents a pinned object to which var object 414 is rootedor attached, and object graph 412 represents an object relationshipgraph of objects in the scripting engine memory space that are managedby a memory system manager. The scripting engine memory space has accessand/or bindings to the layout engine memory space through access links,such as links 418, 420.

In the illustrated and described embodiment, each side of the memorymodel includes at least some objects that are associated with at leastone object on the other side of the memory model. For example, CBaseobject 404 is linked and/or bound to var object 416 through linkage 420,and CBase object 402 is similarly linked and/or bound to var object 414through linkage 418. Various mechanisms can be used to link and/or bindobjects, as further discussed below.

In some embodiments, CBase objects 402, 404 contain actualimplementations for functionality, which can be accessed via directfunctions and/or type operations configured to proxy or “forward”requests from the scripting engine to the CBase objects 402,404. Forexample, a script running in the scripting engine has access to varobjects 414, 416, which are native to the scripting engine memory space.The script does not necessarily have to have knowledge of the associatedCBase objects, nor the associated linkages. Instead, the script canaccess the var objects as native objects to access, request, and/or makecalls or requests associated with certain functionality and information.In turn, direct functions and/or type operations that can be associatedwith var objects 414, 416 can be configured to proxy and/or forward thecall to an associated CBase object for actual execution of the call orrequest. This relationship enables the existence of an object that is,in a sense, dual in nature. Specifically, an object can exist in thelayout engine and can have an associated native representation createdand maintained in the scripting engine.

Part of managing an object's dual nature includes managing a so-calledlifetime relationship between an object in the scripting engine, such asvar object 416, and the corresponding object in the layout engine, suchas CBase object 404. For example, if var object 416 is actively beingused by a script, corresponding CBase object 404 will also be activelyused.

In some cases, the memory management system can implement automaticmemory management, also referred to as “garbage collection”, whichattempts to reclaim memory when the memory is determined to no longer bein use. A more manual method of memory management in a garbage collectedsystem involves pinning an object, such that the garbage collector isnot allowed to reclaim the object memory space until the object ismanually unpinned. If an object is reclaimed prematurely, the linkagebetween the dual nature object can be broken. Conversely, an object canbe marked as active multiple times, thus creating a potential memoryleak, meaning that the memory is not reclaimed, if all of the multipleactive markings are not properly cleared.

In some embodiments, an object graph, such as object graph 412, can bemaintained by a garbage collector to identify what may be a reclaimableobject. An object can maintain active participation in the object graph,and subsequently the garbage collector, through the use of the varobjects. This active participation enables an object to maintain itslifespan without requiring the object to be pinned.

In some embodiments, when a scripting language object associated with adual nature object is created, its identity can be bound with the layoutengine object using an object, referred to herein as“CustomExternalObject,” with expanded custom data, described just below.Furthermore, the CustomExternalObject can expose relationships to agarbage collector, thus enabling the garbage collector to moreaccurately track when an object can be recycled.

As an example, consider FIG. 5, which illustrates an exampleCustomExternalObject 500 in accordance with one or more embodiments.CustomExternalObject 500 includes an object 502, which represents thescripting language object, or var, being created. In some embodiments,the scripting language object is associated with a dual nature object.In addition to object 502, CustomExternalObject includes a number ofpointers, e.g. five pointers: CBase pointer 504, parent var pointer 506,child var pointer 508, previous var pointer 510, and next var pointer512. Through the use of the pointers contained within theCustomExternalObject, relationships between two or more objects can bemanaged.

More specifically, in this particular example, CBase pointer 504 is acode pointer that points back to a layout engine object associated witha dual nature object. This pointer enables access between the scriptingengine and layout engine identities of the dual nature object. Parentvar pointer 506 is a relationship pointer configured to point to aparent var object of object 502. Similarly, child var pointer 508 is arelationship pointer configured to point to a child var object of object502. Previous var pointer 510 and next var pointer 512 are additionalrelationship pointers that are configured to point to siblings of object502, such as, for example, one of five attributes of a parent. Throughthe use of the relationship pointers, object relationships are exposedto the garbage collector. This not only enables the garbage collector tomore accurately manage the lifespan of an object, but to do so withoutrequiring any of the objects to be pinned.

Consider now FIG. 6, which illustrates how the relationship pointerscontained within an expanded CustomExternalObject can be employed inaccordance with one or more embodiments.

FIG. 6 illustrates three CustomExternalObjects—CustomExternalObjects602, 604, and 606, each of which represent var objects created via ascripting engine. Each CustomExternalObject is associated with acorresponding dual nature object. In this particular example,CustomExternalObjects 602, 604 and 606 are associated with objects thathave been created via a layout engine. For instance, CBase pointer 608contains a pointer back to an object in the layout engine that is oftype CElement; CBase pointer 610 contains a pointer back to an object oftype CStyleSheet; and CBase pointer 612 contains a pointer back to anobject of type CAttribute.

Relationships between the layout engine objects, and their associatedCustomExteralObjects 602, 604, and 606, can be expressed in thescripting engine memory space through the use of the additionalrelationship pointers described above. For example, CustomExternalObject604 is a child of CustomExternalObject 602, which is expressed throughlinkage 614 that points the child var pointer of CustomExternalObject602 to CustomExternalObject 604, and through linkage 616, which pointsthe parent var pointer of CustomExternalObject 604 toCustomExternalObject 602. Alternately or additionally, siblingrelationships of objects can be expressed and/or exposed, as illustratedthrough linkages 618, 620. In this particular example,CustomExternalObject 604 is not only a child object ofCustomExternalObject 602, but it is also a sibling ofCustomExternalObject 606. As such, the next var pointer ofCustomExternalObject 604 points to its next sibling,CustomExternalObject 606, as illustrated with link 618. Additionally,CustomExternalObject 606 points to its previous sibling,CustomExternalObject 604, as further illustrated with link 620. Throughthe use of this multi-dimensional, doubly-linked list, objects can beexposed to the scripting engine memory manager without requiring all ofthe objects to be pinned. In some embodiments, a head or main object canbe pinned in memory to anchor the main object from unintendeddestruction and/or recycling from the memory manager.

Additional objects can be rooted to the main object, such as through thedoubly-linked list, thus enforcing some protection against the objectsbeing prematurely recycled. For example, when an object is created, itcan call a function to determine whether it should be pinned in memory,or rooted to another object. If it is determined that the object shouldbe rooted to an object, the associated relationship pointers can be setaccordingly, such as through functions that setup parent/childrelationships between objects, or functions that setup siblingrelationships between objects.

In some embodiments, the layout engine can create a CustomExternalObjectand pass the object to the scripting engine. For example, the layoutengine can support an API configured to be callable by the scriptingengine. Through execution of API calls, the layout engine can create atleast one CustomExternalObject that is native to the scripting enginememory space, include in the CustomExternalObject(s) information thatenables the scripting engine to access the layout engine, and return theCustomExternalObject(s) to the calling scripting engine. Alternately oradditionally, APIs can be configured to support an ability for elementsand/or objects to be inserted into and/or removed from the doubly-linkedlist supported within a CustomExternalObject.

FIG. 7 is a flow diagram that describes steps in a method in accordancewith one or more embodiments. The method can be performed by anysuitable hardware, software, firmware, or combination thereof. In atleast some embodiments, aspects of the method are performed by suitablyconfigured object integration and memory model software executing on acomputing device such as browser 110 and/or layout engine 112 of FIG. 1.

Step 700 creates a layout engine object. The creation of the layoutengine object can be performed in any suitable manner, such as throughan API call, at startup, through receipt of a message, and/or event, andthe like. Alternately or additionally, the layout engine object can bean object created by the layout engine that is independent of the layoutengine application, such as a document being rendered by the layoutengine, an element of the document, and the like. Step 702 creates ascripting language object. Any suitable object can be created, such as aCustomExternalObject as described above. The scripting language objectincludes any object native to the scripting engine memory space that isaccessible through native methods of the scripting language. Alternatelyor additionally, an object native to the scripting engine can includeany object managed by a memory manager of the scripting engine.

Step 704 binds the layout engine object to the scripting languageobject. Any suitable method can be utilized, examples of which areprovided above and below.

Having considered object integration and a corresponding memory model,consider now a discussion of features that enable direct systemintegration in accordance with one or more embodiments.

Direct System Integration

In some embodiments, binding between the Web browser's layout engine andthe scripting engine can include or otherwise utilize features thatenable unified programming access between the layout engine and thescripting engine, such as enabling a programmer to access each side of adual-nature object in a consolidated manner. The features can enhancememory management, enable direct access between the layout engine andscripting engine, and/or enable mutability of a dual nature object, suchas the dual nature objects described above.

FIG. 8 illustrates, in accordance with one or more embodiments, anexpanded view of features included in a binding module, such as, forexample, binding module 116 of FIG. 1. In some embodiments, the featuresdescribed just below can be part of an architecture designed tointegrate a layout engine and a scripting engine in a seamless manner.While FIG. 8 illustrates binding module 116 as including a combinationof features and/or modules, it is to be appreciated and understood thatany combination of features can be included and/or excluded withoutdeparting from the claimed subject matter. Moreover, while theillustrated features are shown as separate modules, it is to beappreciated and understood that one or more feature can be implementedas one module, separate modules, or any combination thereof.

Binding module 116 includes, in this particular example, one or moreDynamic Type System Deferred Initialization modules 802, one or moreDynamic Type System Direct Functions modules 804, one or more DynamicType System Object Proxy modules 806, one or more Dynamic Type SystemOverlay modules 808, one or more Dynamic Type System Re-initializationmodules 810, one or more Accessor Property modules 812, one or moreReplacement Property modules 814, and one or more Dead Code Eliminationmodules 816, each of which is described below. As a somewhat high leveloverview of these features, consider the following discussion, which isthen followed by a discussion of each feature under its own sub-heading.

In one or more embodiments, Dynamic Type System Deferred Initializationmodule 802 enables one or more dynamic type system objects to beinitialized when requested and/or as needed, as will become apparentbelow.

In some embodiments, Dynamic Type System Direct Function module 804 canbe configured as a redirect structure, such as Trampoline 212 of FIG. 2.Dynamic Type System Direct Function module(s) 804 enable one or morefunction instance to be built directly into a scripting engine as anative object. Alternately or additionally, Dynamic Type System DirectFunction module(s) 804 can be configured to generate a call from thenative object to a layout engine backing object. A backing object is anobject that can implement, enforce, and/or execute requestedfunctionality.

In one or more embodiments, Dynamic Type System Object Proxy module 806enables a backing object, such as an object in a layout engine, tooverride or alter the behavior of an associated scripting engine object.

In one or more embodiments, Dynamic Type System Overlay module 808enables script running in a scripting engine to replace, modify, and/oreliminate an API associated with a corresponding layout engine object,as further described below.

In one or more embodiments, Dynamic Type System Re-initialization module810 is configured to enable re-initialization of one or morecross-boundary objects, such as, by way of example and not limitation,object(s) that are transferred to a different type system.

In one or more embodiments, Accessor Property module 812 enables getterand setter functionality of a layout engine object to be exposed andintegrated with an associated scripting language object in a manner thatis native to the scripting language, as further described below. Getterand setter functions can be configured to execute certain functionalitywhen a variable or object is accessed.

In one or more embodiments, Replacement Property module 814 can beconfigured to enforce a read-only property assignment to an object, suchthat values associated with the object can be redirected to anotherassociated object.

In one or more embodiments, Dead Code Elimination module 816 isconfigured to make code execution more efficient. In some embodiments,Dead Code Elimination module 816 can be configured to skip execution ofcode determined to have no intended recipient, as will be describedbelow.

Having described a high level overview of various features included inbinding module 116, consider now a more detailed discussion of eachfeature.

Dynamic Type System Deferred Initialization

Some initialization systems can include a number of objects, e.g., 500objects and even more functions, e.g. 3000 functions. In someapproaches, the entire dynamic type system can be loaded, up front, inthe scripting engine. Needless to say, the time taken to do so can takea significant amount of startup time. This time can be compounded when,for example, a Web page has many frames (e.g., for ads and the like) andeach frame has to load the dynamic type system. In one or moreembodiments, a “deferred” type system initialization can be utilized tobuild the dynamic type system in an “on demand” fashion. Doing so canmitigate in the time impact of loading and entire dynamic type systemupfront. Thus, when no DOM APIs are utilized, very little type systeminitialization cost is incurred. As each new type is needed by, forexample, a return value, the approaches described below can create thetype and its dependent types and functions just before they are needed.This can amortize the initialization cost of used DOM types, and caneliminate the costs entirely for unused types.

In some embodiments, one or more types in a type system can beinitialized in a cascaded, as-needed manner. For example, a particulartype in the type system can be initialized in multiple stages such thatthe particular type becomes accessible and substantiated in the typesystem after all stages have completed. Information concerning the typesin the type system can be initially exposed, declared, or have anassociated identifier such that the type system is aware of the types.However, full initialization of the type(s) can be staggered and/ordeferred, until the type(s) is/are to be accessed. Alternately oradditionally, if a type does not get accessed, it does not become fullysubstantiated, thus reducing the number of objects created in memory.For example, deferring initialization can reserve memory usage for onlythose objects being actively used.

In one or more embodiments, a base set of information associated with atleast one type can be exposed in a type system to a script and/orscripting engine. The base set of information can be associated with anysort of type, such as, by way of example and not limitation, an object,method, property, prototype, and the like. In some embodiments, the baseset of information comprises constructors associated with the type(s).Based upon the information, the script and/or scripting engine caninspect the various types that are available for access. In someembodiments, the script and/or scripting engine can inspect the varioustypes without dynamically querying and/or binding to the types. Forexample, the various types can initially be exposed in the type systemat startup. Runtime performance can improve by reducing or eliminatingthe need for queries, which can be a time consuming operation. Instead,the script and/or scripting engine can have knowledge of the varioustypes through the initial information, and access the types accordinglywithout further steps in the script.

Upon accessing a type associated with the base set of information,constructors of the type can be configured to point and/or link toassociated prototype information. In some embodiments, the constructorscan be configured to point to parent, sibling, and/or childassociations. Alternately or additionally, requesting a particular typeor prototype can further enable associated prototypes, such as parent orsuper-prototypes of the particular type, to become available for access.Linking prototype information of associated types can enable a series ofrelationships between a set of objects and/or prototypes, thus furtherreducing redundant code between the object(s).

Responsive to pointing and/or linking one or more particular prototype,constant properties and/or methods of the particular prototype(s) can beinitialized. For example, the properties and/or methods can be createdin memory and initialized with default values. Alternately oradditionally, the initialized properties and/or methods can be attachedto the particular prototype(s).

Responsive to initializing the properties and/or methods, an instancetype operation is created and tied to an associated object in the layoutengine. For example, the instance type operation can be configured tocreate a var object in the scripting engine environment and bind the varobject to its associated layout engine object, examples of which areprovided above and below.

As an example, consider FIG. 9, which illustrates a flow diagram thatdescribes steps in a method in accordance with one or more embodiments.The method can be performed by any suitable hardware, software,firmware, or combination thereof. In at least some embodiments, aspectsof the method are performed by software, such as a suitably-configuredbinding module, executing on a client device.

Step 900 exposes a base set of information associated with one or moretypes to a type system. For example, the base set of information caninclude one or more constructors associated with the type(s). In someembodiments, the base set of information can be exposed to the typesystem statically at startup.

Responsive to access to the base set of information, step 902initializes at least one link to at least one prototype implementationassociated with the one or more types. For example, a constructor can beconfigured to point to an associated prototype implementation. Accessingthe constructor can cause the link to the associated prototypeimplementation to be initialized.

Step 904 initializes the associated prototype implementation and, insome embodiments, the initialized prototype implementation can beattached to the type being initialized.

Step 906 creates an instance object associated with the initializedtype, and further binds the instance to a backing object, such as anobject in a layout engine. In some embodiments, the instance object canreside in a scripting engine's memory space, while the backing objectresides in the layout engine, as described above.

Deferring and/or cascading initialization of types in a dynamic typesystem as described above enables the types to be built when accessed inan efficient manner, in addition to reserving memory for objects beingactively utilized. Having considered Dynamic Type System DeferredInitialization, consider now a discussion of Dynamic Type System DirectFunctions.

Dynamic Type System Direct Functions

In some systems, functions were previously treated as host objects andwere queried using a particular interface in a two-step process. First,the name of the function was queried to retrieve an ID, and then withthe ID, the function was invoked. This two-step process was found to bevery costly and inefficient, especially when it was used repeatedly.

In one or more embodiments, this two-step process can be eliminatedentirely for objects in the dynamic type system. Objects can be builtdirectly as native scripting engine (e.g., JavaScript objects) and canbe accessed using an associated internal lookup process. Functioninstances can also be built directly into the scripting engine and arelooked up using the same process. When the direct function is obtained,for example using the scripting engine lookup process, its invocationgenerates a call to the DOM's trampoline. The trampoline is able toperform caller validation to take parameters that are passed in and theinvoking object(s) to ensure that only objects of the correct type canperform the invocation. In one or more embodiments, this can be done bycasting to a base object, retrieving the object's type ID information,comparing against a set of allowed type IDs.

More specifically, in some embodiments, a bridge function, also known asa direct function or a “trampoline” as mentioned above, can be createdto bridge calls between the scripting engine and the layout engine. Ascripting language function can wrap the bridge function such that thescripting engine can look-up and access the bridge function throughmethods used to access objects native to the scripting engine (e.g.,through its internal look up process mentioned above). The bridgefunction can be further configured to marshal incoming parameters to anassociated layout engine object and call into one or more methods of theassociated layout engine object. Alternately or additionally, the bridgefunction can be further configured to enable validation of callers ofthe function, such as validation of the callers being of the correctcalling type, as mentioned above.

Objects built directly into and/or via the scripting engine can beaccessed by the scripting engine using native methods. For example, anobject created via a scripting language can be accessed by the scriptingengine using native look-up methods as mentioned above. In someembodiments, a scripting language function can wrap a bridge function,thus enabling the scripting engine to access the bridge function via thewrapped function. Since the wrapped function is native to the scriptinglanguage, it can be manipulated by the scripting language and/orscripting engine as other native objects. For example, in someembodiments, the wrapped function can be attached and/or rooted to otherobjects which, in turn, can attach the associated functionality to theother objects.

As an example, consider FIG. 10, which illustrates variousrelationships, associated with a bridge function, in accordance with oneor more embodiments. White boxes represent functionality implemented ina scripting language, while grey boxes represent functionalityimplemented outside of the scripting language, for example, in C++. FIG.10 includes one or more scripting language wrapper functions 1002, oneor more bridge functions 1004, one or more layout engine objects 1006and one or more Marshal/De-Marshal modules 1008. Additionally, FIG. 10includes flows 1010, 1012 and 1014, which represent one or more callsinto Scripting Language Wrapper function 1002, into Marshal/De-Marshalmodule 1008, and Layout Engine object(s) 1006, respectively. While thearrows are illustrated as a one-way arrow for simplicity of description,it is to be appreciated that the flow of function calls can be two-waywithout departing from the scope of the claimed subject matter.

Scripting language wrapper function 1002 represents a scripting languagefunction that wraps bridge function 1004. Scripting language wrapperfunction 1002 is native to the scripting language, thus allowing thescripting language to call and manipulate the function using standardprocedures, such as those described above. Scripting language wrapperfunction 1002 includes information that enables the wrapper function tocall into bridge function 1004.

Among other things, bridge function 1004 can be configured performvarious forms of validation. For example, in some embodiments, bridgefunction 1004 can be configured to perform caller validation. Callervalidation ensures that only objects of the correct calling type arecalling the function. This can be achieved in many ways, such as byutilizing object type identification (ID) information. In someembodiments, as noted above, an object can be cast to a base object, andits associated ID information can be compared against a set of allowedtype IDs. The set of allowed type IDs can also be configured to reflectallowed types included in one or more hierarchical relationships.Alternately or additionally, bridge function 1004 can be configured tovalidate one or more parameters being passed into the function.

Bridge function(s) 1004 can also be configured to direct calls into oneor more associated layout engine objects. In some embodiments, bridgefunction 1004 can direct a call to an associated layout object aftervalidation has been performed and/or passed, examples of which areprovided above. Furthermore, the call to an associated layout object canbe directed through any suitable method, such as through one or moreAPIs of the layout object. Parameters can be passed by bridge function1004 through the use of marshal/de-marshal module 1008.Marshal/de-marshal module 1008 represents functionality that enablesobjects and/or data to be transferred from one program to another, suchas from a scripting engine to a layout engine.

Layout engine object 1006 represents any sort of object, function, andthe like, associated with a layout engine. For example, layout engineobject 1006 could be a document rendered by a layout engine, an elementwithin the document, and the like. Layout engine object 1006 includesexternally exposed methods, functions, and other forms of access thatenable objects external to layout engine object 1006 to requestfunctionality from the layout engine object, as well as exchange data.In some embodiments, data can be exchanged through the use ofmarshal/de-marshal module 1008.

Flows 1010, 1012, and 1014 represent one example of how the variousfunctions and/or modules can interact. Flow 1010 represents a call froma scripting engine to scripting language wrapper function 1002. Asdiscussed above, the scripting engine can call scripting languagewrapper function 1002 in any manner native to the scripting engine. Upongetting called, as shown by flow 1010, scripting language engine wrapperfunction 1002 calls into bridge function 1004. Upon determiningparameters need to be passed, in some embodiments, bridge function 1002can utilize or call marshal/de-marshal module 1008, as illustrated byflow 1012. Marshal/de-marshal module 1008, in response, can pass theparameters into layout engine object 1006, as illustrated by flow 1014.Alternately or additionally, bridge function 1004 can have direct accessinto layout engine 1006 via APIs, which is not illustrated in FIG. 10.

Bridge functions in combination with scripting language wrapperfunctions facilitate efficient access between a layout engine and ascripting engine. Additionally, the combination further enables objectsto be requested in a manner native to scripting engine, but validatedvia the layout engine, as discussed above. Having described Dynamic TypeSystem Direct Functions, consider now a discussion of Dynamic TypeSystem Object Proxies.

Dynamic Type System Object Proxies

Some DOM objects have special capabilities beyond those available tonative scripting engine objects. For example, if a DOM supports a typeof “dynamic array” whose contents change and update as page elements areadded and/or removed, by moving DOM objects into the scripting enginevia the dynamic type system, these extra capabilities are not providednatively by the scripting engine. In order to facilitate these featuresvia the scripting engine objects, e.g., JavaScript objects, a proxywrapper known as the “type operations” is provided to all objects.

Thus, various embodiments enable a layout engine object to overridecapabilities of an associated scripting engine object. In one or moreembodiments, the proxy wrapper can be provided to the scripting engineobject such that generic or native scripting language operations can beassociated with and/or applied to the scripting engine object. In someembodiments, the proxy wrapper can be modified by the layout engineobject to include additional and/or alternate behavior.

As discussed above, a dual nature object can comprise a scriptinglanguage object and a layout engine object. The scripting languageobject can be embodied as any type of object native to the scriptinglanguage, such as an object, function, and/or prototype that can becreated in the scripting language memory space. Similarly, the layoutengine object can be embodied as any type of object generated in and/orby the layout engine in the layout engine memory space, examples ofwhich are provided above. In some embodiments, the layout engine objectcan alter properties, functions, and/or behavior associated with thescripting language object. For example, type operations associated withthe scripting language object can execute native behavior of thescripting language. In some cases, the native behavior of the scriptinglanguage may be different or out of sync with behavior that is native tothe associated layout engine. For instance, some features or extracapabilities, as noted above, supported by layout engine may not havecomparable native support in the scripting language. The layout engineobject can alter a type operation of the scripting language object toinclude additional and/or completely different behavior when called. Anysuitable type of alteration can be included, such as an ability tosupport a dynamic array as mentioned above, where contents of the arraycan be updated, added, and/or removed. Further examples include usingtype operations to provide overrides for getting and setting properties,property detection, as well as control over when the type operationsshould be used, e.g. during the JavaScript lookup operation process orafter it fails to locate a property via the same process. Through thesealterations, the layout engine object can modify or add behavior to thescripting language object to mimic its own native behavior.

Consider FIG. 11, which illustrates a flow diagram that describes stepsin a method in accordance with one or more embodiments. The method canbe performed by any suitable hardware, software, firmware, orcombination thereof. In at least some embodiments, aspects of the methodare performed by suitably configured software executing on a computingdevice such as binding module 116, layout engine 112, and/or scriptingengine 118 of FIG. 1.

Step 1100 creates a layout engine object. The creation of the layoutengine object can be performed in any suitable manner. Any suitable typeof layout engine object can be created, examples of which are providedabove. Step 1102 creates a scripting language object, such as an objectthat is native to a scripting engine memory space. Step 1104 modifies atype operation associated with the scripting language object to modelbehavior native to the layout engine object, examples of which areprovided above and below.

Having described dynamic type system object proxies, consider now adiscussion of dynamic type system overlay.

Dynamic Type System Overlay

APIs in the dynamic type system are mutable versus the legacy-typesystem which was static and could only be altered in very limited ways.Thus, JavaScript programs can replace “built-in” DOM APIs with theirown, cache and call the APIs, or even delete the APIs outright. In theseinstances, this only affects the direct function entry points and notthe static DOM which supports the code behind them.

In one or more embodiments, the mutability (or lack thereof) iscontrolled via individual property's property descriptor. Propertydescriptors have meta-information that is consumable by the scriptingengine, e.g., the JavaScript engine. Property descriptors providecontrol enumerability, configurability (e.g., whether an API can bechanged or deleted), and a write-ability (e.g., whether data propertiesor fields can have their values changed).

In one or more embodiments, once the APIs have been initialized into thescripting engine, e.g., JavaScript engine, built-in scripting engineAPIs work on associated objects as if they are native objects. Forexample, an operator known as “instanceof” checks whether a giveninstance is a member of a given type. The JavaScript implementation canquery an instance's type, and traverse an associated property's typechain comparing the right-argument to the operator against each DOMtype's prototype object. In one or more embodiments, propertydescriptors are accessed and modified via the same JavaScript nativeAPIs as any other JavaScript object. In this manner, the JavaScriptprogram can dynamically modify the DOM APIs without affecting the staticDOM code. This integration allows greater integration and seamlessbehavior with less complication in overhead.

Consider FIG. 12, which illustrates a flow diagram that describes stepsin a method in accordance with one or more embodiments. The method canbe performed by any suitable hardware, software, firmware, orcombination thereof. In at least some embodiments, aspects of the methodare performed by suitably configured software executing on a computingdevice such as binding module 116, layout engine 112, and/or scriptingengine 118 of FIG. 1.

Step 1200 creates a layout engine object. The creation of the layoutengine object can be performed in any suitable manner. Any suitable typeof layout engine object can be created, examples of which are providedabove. Step 1202 creates a scripting language object, such as an objectthat is native to a scripting engine memory space. Step 1204 modifies,dynamically, at least one API associated with the layout engine objectthrough the scripting language object, examples of which are providedabove and below.

Having described dynamic type system overlay, consider now a discussionof dynamic type system re-initialization.

Dynamic Type System Re-initialization

Various embodiments enable an object native to a scripting engineenvironment to be transferred to a second scripting engine and/or typesystem. Such can mitigate security scenarios where, for example, anobject's type can provide an inadvertent leak of information. In atleast some embodiments, information associated with at least oneproperty and/or prototype of the object can be transferred to the secondscripting engine and/or type system. In some embodiments, an object thathas changed from an initial state can be transferred with its statechanges intact.

In operation, an object can be created that is native to a scriptinglanguage environment. Such can occur, for example, by a scripting enginerunning a script, through the layout engine returning a native scriptinglanguage object to the scripting engine, and the like. At times, thelayout engine may desire to have an object that is native to the firstscripting engine transferred or re-initialized to another scriptingengine. For example, in some instances, the layout engine may desire ascripting language object that has a dual nature, as described above, tobe transferred to a second scripting engine. To do so, attributes of thefirst scripting engine object can be copied and/or translated to asecond scripting engine object, thus effectively transferring orre-initializing the first scripting engine object to the secondscripting engine. In this way, bindings between a dual nature object canbe preserved when transferring between multiple scripting engines.Additionally, in some embodiments, the first scripting language objectcan be removed or deleted without affecting the second scriptinglanguage object.

Additionally, the scripting language can enable properties of the objectto be dynamically changed, such as prototypes, functions, inheritanceand/or property chain, and the like. For example, default values,default properties, default inheritance chains, and the like can bedynamically altered over time. In some embodiments, the alteredproperties of an object in the first scripting engine can be transferredto the corresponding object in the second scripting engine, such as bycopying them. In this manner, static and dynamic changes associated withscripting objects can be preserved across several boundaries.

Consider FIG. 13, which illustrates a flow diagram that describes stepsin a method in accordance with one or more embodiments. The method canbe performed by any suitable hardware, software, firmware, orcombination thereof. In at least some embodiments, aspects of the methodare performed by suitably configured software executing on a computingdevice such as binding module 116, layout engine 112, and/or scriptingengine 118 of FIG. 1.

Step 1300 creates a first scripting language object that is native to alanguage of a first scripting engine. The creation of the firstscripting language object can be performed in any suitable manner.Alternately or additionally, any suitable type of scripting languageobject can be created, examples of which are provided above. Step 1302creates a second scripting language object that is native to a languageof a second scripting language. In some embodiments, the first andsecond scripting languages are not the same language. In otherembodiments, the first and second scripting languages are the same. Step1304 copies, at least in part, attributes associated with the firstscripting language object from the first scripting engine to the secondscripting language object. Any suitable attribute can be copied, such asa pointer, a value, a data structure, and the like. In some embodiments,bindings included in the first scripting language object can be copiedto the second scripting language object. Alternately or additionally, atranslation and/or transformation can be applied to an attribute toconfirm to the second scripting language.

Accordingly, scripting language objects can be transferred acrossboundaries of multiple scripting engines and/or type systems whilepreserving properties of the objects, such as inheritance, prototypes,and the like. Having described dynamic type system re-initialization,consider now a discussion of accessor properties.

Accessor Properties

Various embodiments enable direct access to getter and setter accessorsof a dual nature object. Getter accessors can be called separately fromsetter accessors using unique signatures for each.

Accessors enable access to a property, variable, and/or value withoutdirect exposure of an associated object. For example, a script can set avalue or property of an object by calling a setter accessor, without thescript having direct access to the associated object or variable storingthe value and/or property. Similarly, the script can get a value orproperty by calling a getter accessor. In some embodiments, getter andsetter functionality of the layout engine object can be exposed andintegrated with an associated scripting language object in a manner thatis native to the scripting language. For example, direct functions canbe used to integrate accessors associated with the layout engine objectinto the scripting engine.

In some embodiments, each accessor can have a unique signature. Forexample, different direct functions can be used for a getter and setter,respectively. This enables a script, object, prototype, and the like, tocall each getter and setter uniquely. Thus, direct functions can be usedto enable access from a scripting engine to accessors associated withlayout engine objects. Through the use of unique direct functions foreach setter and getter, setter and getter functions can be calleddirectly instead of passing one or more parameters to a shared functionor ID in order to distinguish between the two.

Consider FIG. 14, which illustrates a flow diagram that describes stepsin a method in accordance with one or more embodiments. The method canbe performed by any suitable hardware, software, firmware, orcombination thereof. In at least some embodiments, aspects of the methodare performed by suitably configured software executing on a computingdevice such as binding module 116, layout engine 112, and/or scriptingengine 118 of FIG. 1.

Step 1400 creates a layout engine object. The creation of the layoutengine object can be performed in any suitable manner. Any suitable typeof layout engine object can be created, examples of which are providedabove. Step 1402 creates a scripting language object, such as an objectthat is native to a scripting engine memory space. Step 1404 calls oneor more accessors associated with the layout engine object, through thescripting engine object, without one or more parameters that areconfigured to distinguish between the one or more accessors. Forexample, each accessor can be configured to have a unique signature, asdescribed above.

Having described accessor properties, consider now a discussion ofreplacement properties.

Replacement Properties

Various embodiments enable a read-only property to be replaceable.Replace-ability pertains to a situation in which a read-only property ischanged. Specifically, when a read-only property is assigned a value,the original read-only property is removed and the newly assignedproperty takes its place. In one or more embodiments, this semantic issupported by assigning a put accessor value to the read only property.When it is then invoked, an associated interface is used to create a newproperty on the calling instance object that then “shadows” theread-only API. Using this technique, future requests for the read-onlyproperly will correctly obtain the shadowed property instead.Furthermore, if the shadowed property is ever deleted, the originalreplaceable read-only is once again accessible.

Thus, in some embodiments, a replaceable value can be a shadow valueconfigured to virtually replace the read-only property. Alternately oradditionally, a setter accessor associated with the read-only propertycan be implemented to mimic read-only behavior.

In some embodiments, a read-only property of a layout engine object canbe configured to be replaceable in the manner just described. Forexample, in a dual nature object such as those described above, thescripting language object can be configured to virtually set thereplaceable read-only property value on the scripting engine side,without physically replacing the layout engine object value. A shadowvalue can then be stored as a field on an instance object associatedwith the scripting language object. When a script or object queries theread-only property, the shadow value can then be returned. In one ormore embodiments, deleting the shadow value, as mentioned above, canthen restore the read-only property to an original value, such as thatof the layout engine object.

For example, consider FIG. 15, which illustrates a process diagramdescribing read-only replaceable properties. When attempting to access aread-only replaceable property, the scripting language lookup pathbegins at instance object 1500. From instance object 1500, the lookuppath moves to associated prototype object 1502. In some embodiments,prototype object 1502 can comprise read-only (replaceable) property 1504which can be an accessor property. Each accessor (e.g. getter andsetter) can be configured as a direct function into an associated layoutengine object. Further, setter direct function 1506 can be configured tocreate (new) field property 1508 associated and/or attached to instanceobject 1500 when invoked with a value. In future calls through thescripting engine lookup path, since instance object 1500 resides firstin the path, field property 1508 will be found first and the valuereturned.

As a further example, consider FIG. 16, which illustrates a flow diagramthat describes steps in a method in accordance with one or moreembodiments. The method can be performed by any suitable hardware,software, firmware, or combination thereof. In at least someembodiments, aspects of the method are performed by suitably configuredsoftware executing on a computing device such as binding module 116,layout engine 112, and/or scripting engine 118 of FIG. 1.

Step 1600 creates a layout engine object. The creation of the layoutengine object can be performed in any suitable manner. Any suitable typeof layout engine object can be created, examples of which are providedabove. Step 1602 creates a scripting language object, such as an objectthat is native to a scripting engine memory space. Step 1604 virtuallysets a replaceable read-only property of the layout engine object,through the scripting language object, without physically replacing thelayout engine object property, such as through a shadow value asdescribed above.

Having described replacement properties, consider now a discussion ofdead code elimination.

Dead Code Elimination

Various embodiments enable an evaluation of code usage and forefficiencies to be enhanced through so-called dead code elimination. Insome embodiments, execution of the code can be prevented based upon thisevaluation.

In one or more embodiments, code can be evaluated to determine whetherits associated output used. For example, in some embodiments, a functionand/or prototype can return data such as a value, string, object, andthe like, to an intended recipient. Usage of the returned data can beevaluated and, if it is determined that the returned data is not to beused, execution of associated code can be prevented. For example, ifthere is no such intended recipient for the returned data, code thatordinarily converts the returned data can be skipped thus savingprocessing time and improving performance. If the returned data doeshave an intended recipient, then the associated code is allowed to run.

Having discussed dead code elimination, consider now a discussion of asecurity model in accordance with one or more embodiments.

Security Model

Various embodiments enable secure interactions between scripting enginesresiding in separate domains. In some cases, protections can be employedto prevent object access and/or restrict access to type systeminformation. Alternately or additionally, in some embodiments, functionsthat include cross-domain access functionality can be marked as safe,thus allowing cross-domain access. In some embodiments, a sub-windowproxy can provide secure access across multiple domains to one or moresub-objects associated with a window.

As an example, consider FIG. 17, which illustrates an expanded view offeatures included in a security module, such as, for example, securitymodule 118 of FIG. 1. In some embodiments, the features described belowcan be part of an architecture designed to enforce security within alayout engine and/or a scripting engine, such as cross-domain security.While FIG. 17 illustrates security module 118 including a combination offeatures and/or modules, it is to be appreciated and understood that anycombination of features can be included and/or excluded withoutdeparting from the claimed subject matter. Moreover, while theillustrated features are shown as separate modules, it is to beappreciated and understood that one or more feature can be implementedas one module, separate modules, or any combination thereof.

In the illustrated and described embodiment, security module 118includes one or more static property descriptor modules 1702, one ormore API restriction modules 1704, one or more safe API identificationmodules 1706, one or more reflect function modules 1708, one or moresub-window proxy modules 1710, and one or more same-origin optimizationmodules 1712.

In one or more embodiments, static property descriptor module 1702enables configuration of access to a property descriptor, as will befurther discussed below.

In one or more embodiments, API restriction module 1704 enables theability to block access to internal library APIs of a scriptinglanguage. In some embodiments, access to the APIs can be blocked basedupon a current state of a caller, such as whether the caller is in asame-domain or a different domain.

In one or more embodiments, safe API identification module 1706 enablesthe ability to mark one or more APIs as being safe APIs to call. Atleast some of the marked APIs can be APIs configured to enablecross-domain access.

In one or more embodiments, reflect function module 1708 enablesfunction objects to be exchanged across domains without exposingassociated type system information. The exchanged function objects canbe configured to be created in a type system associated with a caller,as will become apparent below.

In one or more embodiments, sub-window proxy module 1710 enables anability to have sub-windows that inherit security properties of aprimary window. Security decisions of the sub-window can be proxiedand/or deferred to the primary window.

In one or more embodiments, same-origin optimization module 1712 enablessame-origin security checks to be bypassed, as will be further describedbelow.

Having described an overview of various features included in securitymodule 118, consider now a more detailed discussion of each featureunder its own respective sub-heading.

Static Property Descriptor Module(s)

Various embodiments enable an ability to configure access to a propertydescriptor. For example, individual attributes associated with aproperty descriptor can be configured to allow and/or disallow certainforms of access to the property descriptor. For example, a propertydescriptor can be configured to be visible, not visible, writable,mutable, un-mutable, configurable, and the like. In a dynamic typesystem, when a property descriptor is marked as un-mutable, it cannot bedynamically changed, effectively making the property descriptor static.Altering the property descriptor's accessibility and/or configurabilitycan restrict access and/or alterations to the property descriptor.

In one or more embodiments, during a definition phase of the propertydescriptor, tags can be included in the definition to describe variousattributes associated with the property descriptor. For instance,meta-data can be included and/or associated with a property descriptordefinition to define one or more attributes of the property descriptor,as will be further described below. A scripting engine can then beconfigured to recognize, support, and/or enforce the attributes asspecified.

Utilizing configurable attributes as described above can prevent scriptfrom altering property descriptors, thus ensuring a more secureenvironment. Having described static property descriptors, consider adiscussion of API restriction modules.

API Restriction Modules

In one or more embodiments, access to library functions of a scriptinglanguage can be altered or restricted to adhere to security policies.For example, access to an API of the scripting language can beconditionally blocked and/or restricted to prevent the API from workingin cross-domain conditions. The API can be any form of library functionsuch as, by way of example and not limitation, defineProperty( ),getOwnPropertyDescriptor( ), HasAccessor( ), getPrototypeOf( ), and thelike. A type operation of the API can be modified and/or replaced toenforce security policies. For example, when the API is called, themodified type operation can determine whether access is to be granted ornot based upon the security policies. In some embodiments, when it isdetermined to not grant access, access can be disabled and/or anexception can be thrown.

Security policies can include any form of policy, such as a policy thatis associated with whether a caller of the library function is in thesame domain or not. In some embodiments, when the library function iscalled across separate domains, access to the function can be blocked.

Restricting access to library functions of a scripting language canprevent unwanted cross-domain access to objects and/or type systems.Having described API restriction modules, consider now a discussion ofsafe API identification modules.

Safe API Identification Module(s)

Various embodiments enable functions to be configured as so-called safefunctions. An API included in a library and/or associated with an objectcan be marked as “safe”, while other associated functions and/orproperties are disallowed. In at least some embodiments, functions canbe selectively marked as allowable, regardless of what type ofinformation can be accessed via the function. For example, a functionthat enables cross-domain access can be marked as safe. Being marked assafe allows the function to execute regardless of what state it is beingcalled in, such as across multiple domains. For example, tags and/orattributes can be assigned to an API during its definition phase to markthe API as a safe API, as further described below. In a dual natureobject, enforcement of the allowed and/or disallowed API can occur onthe layout engine side of the dual nature object.

Having described safe API identification, consider now a discussion ofreflect functions.

Reflect Functions

In one or more embodiments, a function object can be returned across oneor more domains without divulging type system information associatedwith the function's origins. The function object can be wrapped with afunction and/or associated with a proxy object, where the wrappedfunction and/or associated proxy object is returned across the multipledomains. In some embodiments, the wrapped function and/or proxy objectcan be configured to be actualized in the type system of the receivingdomain.

In one or more embodiments, cross-domain access to a function object canbe allowed without divulging type system information of the functionobject's origins. For instance, script residing in a first domain canrequest access to a function object in a second domain. The functionobject inherently includes type system information associated with itstype system of origin. This inherent type system information can beobscured from external domains and/or type systems, such as through theuse of a wrapper function and/or proxy object. When a function object isrequested across domains, the wrapper function and/or proxy object canbe returned instead of the function object. The wrapper function and/orproxy object can be further configured to direct calls to the functionobject, thus enabling indirect access to the function object. Forexample, the wrapper function and/or proxy object can allow safe accessto all of the associated capabilities of the function object, such ascall, apply, bind, constructor, and the like.

In some embodiments, the wrapper function and/or proxy object can directcalls without exposing type system information associated with thefunction object's origin. For example, the wrapper function and/or proxyobject can be configured to instantiate in the type system of thecalling type system. By instantiating in the type system of the callingsystem, attempted access to type system information of the wrapperfunction and/or proxy object yields type system information of thecalling system. The calling system can call the wrapper function and/orproxy object in methods native to the calling system for access to theoriginal function object.

Through the use of wrapper functions and/or proxy objects, functionobjects can be accessed across multiple domains without exposing anytype system information associated with the function objects. Havingdiscussed reflect functions, consider now a discussion of sub-windowproxies.

Sub-Window Proxies

In one or more embodiments, one or more sub-window proxies can beassociated with a primary type system window proxy. The sub-window proxycan be configured to assert at least some security policies associatedwith the primary window proxy. Alternately or additionally, thesub-window proxy can exist independent of the primary window proxy.

At times, a window associated with a window proxy can have objectsunderneath the window that are accessible. The window proxy enablesmultiple domain access to the associated window. For example, the windowproxy can proxy, by way of example and not of limitation, propertydetection, built-in read/write/execute requests, user-defined propertyread/write/execute requests, library object access, array indexaddressing, custom name resolution, enumeration, and the like, to theassociated window. In some embodiments, objects underneath the windowcan be accessed, such as through a sub-window proxy. For instance, anobject returned from a safe API as described above can be returned as asub-window proxy. As in the case of the window proxy, the sub-windowproxy can be configured to proxy the capabilities of its correspondingobject.

In some embodiments, the sub-window proxy can assert at least thesecurity policies associated with its primary window proxy. Forinstance, the sub-window proxy can be configured to defer securitydecisions to its primary window proxy. Alternately or additionally, thesub-window proxy can exist independently of its primary window proxy. Insome embodiments, the sub-window proxy can be configured to bedynamically updated to reflect contents of a new window's sub-object.

Accordingly, sub-window proxies can enable cross-domain access toobjects that are sub-objects associated with a window, without exposingtype system information associated with the sub-objects. Havingdescribed sub-window proxies, consider now a discussion of globaloptimization for same-origin requests.

Global Optimization for Same-Origin Requests

Many websites use self-referential properties to explicitly specify thatthey are requesting properties from a global namespace root, e.g.,“window.document”, where “window” is a self-reference to the implicitnamespace root object. In one or more embodiments, self-referentialproperties to a global object, such as a JavaScript global object,return all proxies to that object in order to protect against accidentalor willful disclosure of the global object. However, due to the commonpractice of self-referencing, security checks can degrade performance,even when they are not really necessary. In accordance with one or moreembodiments, to increase performance of the property request under thesecircumstances, the proxy's caller and target can be preemptively checkedto see if they are the same object. If so, expensive security checks canbe safely bypassed without sacrificing the security of the globalobject.

As such, various embodiments can enable security checks to be bypassed,such as when a caller and a target are of the same domain and/or origin.If a caller and a target reside in the same domain, then securitychecks, such as those to protect cross-domain access, can be bypassed.

As an example, consider the following. A secure window object, such as aproxy object, can be utilized and can call into a global object which,in turn, has access to various forms of information and/or codeexecution, such as a trusted window. Responsive to these calls, acomparison can be made to determine whether a caller of the securewindow object and the target of the call, such as the trusted window,reside in the same domain and/or origin. If the caller and the targetare determined to reside in the same origin, security checks can bebypassed. In this instance, bypassing the security checks can be donewithout risk of unintended exposure.

Bypassing security checks on same-origin transactions can enhanceruntime performance by preventing unnecessary code from executing.Having described global optimization for same-origin requests, considernow an example method in accordance with one or more embodiments.

FIG. 18 illustrates a flow diagram that describes steps in a method inaccordance with one or more embodiments. The method can be performed byany suitable hardware, software, firmware, or combination thereof. In atleast some embodiments, aspects of the method are performed by suitablyconfigured software executing on a computing device such as securitymodule 118, layout engine 112, and/or scripting engine 118 of FIG. 1.

Step 1800 creates a layout engine object. The creation of the layoutengine object can be performed in any suitable manner. Any suitable typeof layout object can be created, examples of which are provided above.Step 1802 creates a scripting language object, such as an object that isnative to a scripting engine memory space. Step 1804 uses a securitymodel to provide secure information transfer during access to the layoutengine object and/or the scripting language object, examples of whichare provided above.

Having described various security models in accordance with one or moreembodiments, consider now a discussion of various aspects of InterfaceDefinition Language (IDL) integration in accordance with one or moreembodiments.

Interface Definition Language Integration

In one or more embodiments, extensions to an Interface DefinitionLanguage (IDL) can facilitate and enable direct integration of a layoutengine and a scripting engine.

In one or more embodiments, extended IDL code can be used in conjunctionwith an IDL compiler to enable generation of code configured to bridgethe layout engine and scripting engine. Alternately or additionally,hierarchical relationships between objects and their associated APIs canbe described using the extended IDL. In some embodiments, the extendedIDL can include syntax to describe attributes of the objects and/or theassociated APIs.

As will be appreciated by the skilled artisan, IDL code can be used todescribe one or more interfaces between various software components,such as interfaces between a layout engine and a scripting engine.Extensions to the IDL code, as described herein, can be included tofurther describe objects, APIs defined on the objects, relationshipsbetween the objects, attributes associated with the objects and/or APIs,and the like. A compiler, such as an IDL compiler, can interpret the IDLcode and generate corresponding functions, header files, and the like,to enable the software components access to one another.

As an example, consider FIG. 19, which illustrates a relationshipbetween extended IDL code, a compiler, and associated inputs andoutputs. Here, Property Description Language (PDL) file(s) 1902 andextended IDL file 1904 are received and processed by a compiler 1906 toproduce trampoline function(s) 1908, trampoline definition(s) 1910 andper type initialization function(s) 1912, all of which are describedbelow in more detail.

In the illustrated and described embodiment, PDL files 1902 can includeone or more files that define one or more layout engine programmingobjects and/or their associated APIs. Any suitable type of programmingobject can be defined through a PDL file, such as, by way of example andnot limitation, a COM based object. In some embodiments, PDL files 1902can include one or more files that define one or more scripting languageobjects, such as a dispatch object. Dispatch objects enable a scriptingengine to lookup and/or obtain objects from a layout engine objectthrough dynamic binding, such as through a dispatch method.

In one or more embodiments, extended IDL file 1904 includes alternatedescriptions of at least some of the APIs and objects included in PDLfiles 1904. In some embodiments, an extended property descriptionlanguage and/or extended interface definition interface language is usedto express these alternate descriptions. For example, the extendedlanguage can include additional attributes that can be applied to an APIand/or object, as further described below. In addition to includingattributes, extended IDL file 1904 can include hierarchical relationshipinformation, such as a hierarchical arrangement of APIs. The APIs can bearranged as objects based upon the hierarchical information, thusreducing and/or eliminating redundancy that would be generated fromusing PDL file(s) 1902 without the extended IDL file 1904.

In the illustrated and described embodiment, compiler 1906 acceptsmultiple input files, such as PDL file(s) 1902 and extended IDL file1904, and processes those files to produce trampoline function(s) 1908,trampoline definition(s) 1910, and per type initialization function(s)1912. While illustrated as one module in FIG. 19, it is to beappreciated and understood that compiler 1906 can comprise multiplemodules without departing from the spirit of the claimed subject matter.

In one or more embodiments, trampoline function 1908 includes code thatenables calls between software modules to be bridged, such as dynamictype system direct functions as described above. In some embodiments,trampoline function 1908 can be generated as source code, such as C++implementation files (.cpp files). Of course, other code types can begenerated without departing from the spirit and scope of the claimedsubject matter. Trampoline function 1908 can be partially or fullygenerated by compiler 1906.

In addition to trampoline function(s) 1908, compiler 1906 can generatetrampoline definition(s) 1910. Trampoline definition(s) 1910 can includeone or more definitions and/or forward declarations of associatedtrampoline function(s) 1908, such as forward declarations included in aheader file (.h file).

In some embodiments, per type initialization functions 1912 includeinstructions and/or script written in a scripting language, such asJavaScript and enable initialization of one or more types in a typesystem, e.g., a dynamic type system deferred initialization as describedabove.

In addition to reducing and/or eliminating code redundancy, such asthrough object relationship information, the combined use of PDL file(s)1902 and extended IDL file 1904 enable resultant code to be inspectableby a human prior to further compilation. For example, a developer canadd, delete, and/or modify attributes within the extended IDL file 1904,input the modifications to compiler 1906, and inspect the resultantsource code file(s) prior to generating binary code. This iterativeprocess can enable software deficiencies to be located earlier in adevelopment cycle.

Having discussed PDL and extended IDL files and how they can beprocessed by a compiler, consider now a discussion of an exampleextended IDL file in accordance with one or more embodiments.

FIG. 20 illustrates an expanded view of extensions that can be includedin an extended IDL file, such as, for example, extended IDL file 120 ofFIG. 1. While FIG. 20 illustrates extended IDL file 120 including acombination of features and/or attributes, it is to be appreciated andunderstood that any combination of attributes can be included and/orexcluded without departing from the claimed subject matter.

In this particular example, extended IDL file 120 includes one or moreannotation/documentation attributes 2002, one or more global objectextension attributes 2004, one or more code generation attributes 2006,and/or one or more API availability attributes 2008, each of which isindividually discussed below.

In one or more embodiments, the annotation/documentation attributes 2002enable various forms of additional annotations and/or documentation tobe included in extended IDL file 120 and/or associated output files.Some annotation attributes can be used for hyper-linking, such as byincluding a Uniform Resource Locator (URL). For instance, attributes caninclude links associated with an interface and/or property definitions,such as associated specifications and/or additional documentation on theinterface and/or property definitions. Other annotation attributes canbe used to describe, link, and/or point an interface and/or propertydefinition to an associated binary code representation. In someembodiments, annotation attributes can be used to include releaseinformation, such as API introduction dates and/or times, modificationdate and/or times, author, revision number, and the like. Alternately oradditionally, annotation attributes can include attributes that are usedto extend a property with an associated attribute name and/or CascadingStyle Sheet (CSS) property. For example, in some embodiments, anannotation attribute can be used to include an alternate language nameof the property. Other annotation attributes can be used to includetesting identification references, such as testing identificationreferences that can be used to coordinate a public test suite of anassociated API. In one or more embodiments, an annotation attribute canbe used to include tag identifiers that enable API categorization andsearch-indexing.

In one or more embodiments, global object extension attribute 2004enables control of which interface can be used to extend a scriptingengine's global object. For example, global object extension attribute2004 can identify one or more interface to be grafted as the globalobject. This can enable the existence of alternate forms of extended IDLfile 120 to support different global object integration.

In one or more embodiments, code generation attribute 2006 enablescontrol of how code is generated. For example, some attributes can beused to control security aspects of a property and/or API, such asmarking a property and/or API as a Safe API as described above. Otherattributes can be used to control default initialization of a property,such as configuring the property to be locked-down, un-mutable, notenumerable, and/or not configurable. Through the use of the attributes,properties can be configured independent from one another. For instance,a first property described in extended IDL file 120 can be configured tobe mutable, while a second property in extended IDL file 120 can beconfigured to be un-mutable.

Alternately or additionally, attributes can be used to indicate entrypoints for associated code. For example, attributes can be used todescribe C++ entry points. Other attributes can be used to indicatedefault values to be used for optional pass-in parameters.

In one or more embodiments, API availability attribute 2008 enablesconfiguration of API availability based upon a current environment. Forexample, attributes can be used to enable one or more APIs to beavailable to a Web page running HyperText Markup Language (HTML), but beunavailable to a Web page running eXtensible Markup Language (XML). Insome embodiments, an attribute can be used to mark an API as deprecated,which can trigger removal of the API under XML-based pages.

Having described various extensions that can be included in an IDL file,consider now FIG. 21, which illustrates a flow diagram that describessteps in a method in accordance with one or more embodiments. The methodcan be performed by any suitable hardware, software, firmware, orcombination thereof. In at least some embodiments, aspects of the methodare performed by software executing on a computing device.

Step 2100 receives one or more Property Description Language (PDL)files, examples of which are provided above. Step 2102 receives at leastone extended Interface Definition Language (IDL) file. As describedabove, the extended IDL file can include any suitable combination ofextended attributes, such as annotation attributes, global objectextension attributes, and the like. Step 2104 processes the PDL andextended IDL files to generate at least one header file and associatedsource code file. The header file and associated source code file areconfigured to enable binding of a scripting engine and a layout engine,such as through direct type system direct functions. Step 2106 processesthe PDL and extended IDL files to generate at least one type systeminitialization function. The type system initialization function can beconfigured to enable binding of the scripting engine and the layoutengine, such as through dynamic type system deferred initialization asdescribed above.

Having described of interface definition language integration, considernow a discussion of various aspects of other considerations inaccordance with one or more embodiments.

Other Considerations

In accordance with one or more embodiments, other design considerationcan be taken into account in designing a model to bind a layout enginewith a scripting engine. Consider now the following discussion of alayout engine object and scripting language object integration model.

Layout Engine Object and Scripting Language Object Integration Model

In one or more embodiments, a dual nature object can be configured to beprogrammatically unified between its scripting engine side and itslayout engine side. A scripting language object associated with the dualnature object can be extended from its default state to includeadditional properties and/or prototypes associated with a correspondinglayout engine object, as well as properties and/or prototype inheritedfrom other objects. In some embodiments, APIs of the layout engineobject can be included in a lookup path of the scripting language objectsuch that the APIs can be accessed in a manner native to the scriptinglanguage. In one or more embodiments, a prototype object associated withan API can be created and attached to the scripting language object. Forexample, APIs associated with a window object in the layout engine canbe associated with a prototype object and attached to an associatedscripting language object. Similarly, a web worker's global object canbe extended by attaching a prototype containing APIs associated with alayout engine's web worker global object. In this way, the dual natureobject can be integrated, thus enabling unified programming access.

In some embodiments, a proxy can be configured to forward requests toand from the scripting language object. For example, a window proxy canbe configured to broker calls to the scripting language object whensecurity allows access. At times, direct references to an object can bedisallowed. For example, in a dual nature object, a direct reference tothe underlying layout engine object can be forbidden. In theseinstances, the window proxy can be returned instead of the directreference, thus enabling access to functionality without direct exposureof the object.

Having described an object integration model between a layout engineobject and a scripting language object, consider now a discussion ofbackwards compatibility support that is in accordance with one or moreembodiments.

Backwards Compatibility Support

In one or more embodiments, scripts running in the scripting engine canhave access to layout engine objects via the dual nature objectmentioned above. For instance, scripts can have access to a var objectthat is associated with the layout engine object in order to gain accessand/or call APIs of the layout engine object. In some cases, analternate path can be used to call the APIs. In approaches that utilizea COM based model, a COM based client can utilize methods, such asiUnknown and/or iDispatch, to directly acquire identification and/orinvoke the APIs. Of course, other approaches can be utilized withoutdeparting from the spirit and scope of the claimed subject matter. Inother cases, the COM based client can request more automated access,such as through iDispatchEx, as will be appreciated by the skilledartisan.

In COM based embodiments, when the COM based client calls iUnknownand/or iDispatch, the calls can be forwarded to the layout engine. Thelayout engine is configured to dynamically support these calls. Thelayout engine can create a tear-off object and/or interface to return tothe COM based client. The tear-off object or interface enables dynamicbinding for the requested functionality.

In one or more embodiments, when the COM based client calls iDispatchEx,the call can be forwarded around the scripting engine. In someembodiments, a backchannel can be created between the scripting engineand a scripting engine object. The backchannel can be configured toenable private transactions between the scripting engine and thescripting engine object. For example, through the backchannel, thescripting engine can natively access functionality of the scriptingengine object while appearing to support the iDispatchEx in a moretraditional manner.

Having described backwards compatibility support, consider now adiscussion of support for multiple scripting engines in accordance withone or more embodiments.

Support for Multiple Scripting Engines

In some embodiments, a second scripting engine can be supported throughan extension of a first scripting engine. In a dual nature system, thefirst scripting engine can be configured to look internally first forname resolution. If name resolution is not found in the first scriptingengine lookup process, requests can be routed to the second scriptingengine. The first scripting engine can be extended to support methodinvocations from the second scripting engine.

Having described other considerations, consider now a discussion of anexample system in accordance with one or more embodiments.

Example System

FIG. 22 illustrates an example computing device 2200 that can be used toimplement the various embodiments described above. Computing device 2200can be, for example, computing device 102 of FIG. 1 or any othersuitable computing device.

Computing device 2200 includes one or more processors or processingunits 2202, one or more memory and/or storage components 2204, one ormore input/output (I/O) devices 2206, and a bus 2208 that allows thevarious components and devices to communicate with one another. Bus 2208represents one or more of any of several types of bus structures,including a memory bus or memory controller, a peripheral bus, anaccelerated graphics port, and a processor or local bus using any of avariety of bus architectures. Bus 2208 can include wired and/or wirelessbuses.

Memory/storage component 2204 represents one or more computer storagemedia. Component 2204 can include volatile media (such as random accessmemory (RAM)) and/or nonvolatile media (such as read only memory (ROM),Flash memory, optical disks, magnetic disks, and so forth). Component2204 can include fixed media (e.g., RAM, ROM, a fixed hard drive, etc.)as well as removable media (e.g., a Flash memory drive, a removable harddrive, an optical disk, and so forth).

One or more input/output devices 2206 allow a user to enter commands andinformation to computing device 2200, and also allow information to bepresented to the user and/or other components or devices. Examples ofinput devices include a keyboard, a cursor control device (e.g., amouse), a microphone, a scanner, and so forth. Examples of outputdevices include a display device (e.g., a monitor or projector),speakers, a printer, a network card, and so forth.

Various techniques may be described herein in the general context ofsoftware or program modules. Generally, software includes routines,programs, objects, components, data structures, and so forth thatperform particular tasks or implement particular abstract data types. Animplementation of these modules and techniques may be stored on ortransmitted across some form of computer readable media. Computerreadable media can be any available medium or media that can be accessedby a computing device. By way of example, and not limitation, computerreadable media may comprise “computer-readable storage media”.

“Computer-readable storage media” include volatile and non-volatile,removable and non-removable media implemented in any method ortechnology for storage of information such as computer readableinstructions, data structures, program modules, or other data.Computer-readable storage media include, but are not limited to, RAM,ROM, EEPROM, flash memory or other memory technology, CD-ROM, digitalversatile disks (DVD) or other optical storage, magnetic cassettes,magnetic tape, magnetic disk storage or other magnetic storage devices,or any other medium which can be used to store the desired informationand which can be accessed by a computer.

CONCLUSION

Various embodiments provide an interface between a Web browser's layoutengine and a scripting engine. The interface enables objects from thelayout engine to be recognized by a memory manager in the scriptingengine and interact in a streamlined, efficient manner. In accordancewith one or more embodiments, the interface allows browser layout engineobjects to be created as objects that are native to the scriptingengine. Alternately or additionally, in some embodiments, the nativeobjects are further configured to proxy functionality between the layoutengine and the scripting engine.

In some embodiments, binding between the Web browser's layout engine andthe scripting engine can include features configured to enable unifiedprogramming access between the layout engine and the scripting engine,as well as secured access across multiple domains. The features can beconfigured to enhance memory management, enable direct access betweenthe layout engine and scripting engine, and/or enable mutability of adual nature object.

Although the subject matter has been described in language specific tostructural features and/or methodological acts, it is to be understoodthat the subject matter defined in the appended claims is notnecessarily limited to the specific features or acts described above.Rather, the specific features and acts described above are disclosed asexample forms of implementing the claims.

1. One or more computer readable storage media embodyingcomputer-readable instructions which, when executed, implement a systemcomprising: a web browser configured to create a scripting engine and alayout engine; and, a trampoline logically interposed between thescripting engine and the layout engine and configured to enable functioncalls associated with an object native to the scripting engine to beredirected to an object in the layout engine for work load execution. 2.The one or more computer-readable storage media of claim 1, wherein saidtrampoline is configured to enable communication between the scriptingengine and the layout engine without requesting interface pointers. 3.The one or more computer-readable storage media of claim 1, wherein thescripting engine is associated with a scripting engine memory space andthe layout engine is associated with a layout engine memory space,wherein the scripting engine memory space includes one or more objectsthat are associated with, and bound to one or more objects in the layoutengine memory space through associated linkages.
 4. The one or morecomputer-readable storage media of claim 3, wherein the one or moreobjects in the scripting engine memory space that are bound to one ormore objects in the layout engine memory space serve as proxy objectsthat proxy requests to their associated objects in the layout enginememory space.
 5. The one or more computer-readable storage media ofclaim 3, wherein objects in the scripting engine memory space are boundto objects in the layout engine memory space through linkages thatutilize, respectively, custom objects that represent associated objectsin scripting engine memory space and which include one or more pointers,at least one of which points to an associated, bound object in layoutengine memory space.
 6. The one or more computer-readable storage mediaof claim 5, wherein at least some of the pointers are configured topoint to other objects in the scripting engine memory space.
 7. The oneor more computer-readable storage media of claim 6, wherein said atleast some of the pointers are configured to point to parent objects. 8.The one or more computer-readable storage media of claim 6, wherein saidat least some of the pointers are configured to point to child objects.9. The one or more computer-readable storage media of claim 6, whereinsaid at least some of the pointers are configured to point to siblingobjects.
 10. The one or more computer-readable storage media of claim 5,wherein the one or more pointers comprise relationship pointers that areconfigured to be used for memory management.
 11. The one or morecomputer-readable storage media of claim 1, wherein the system furthercomprises an object graph that is configured to enable memory managementto identify reclaimable objects.
 12. The one or more computer-readablestorage media of claim 11, wherein the object graph is configured toreside in the scripting engine memory space.
 13. The one or morecomputer-readable storage media of claim 11, wherein the object draft isconfigured to enable an object to maintain its lifespan withoutrequiring the object to be pinned.
 14. A computer-implemented methodcomprising: creating a layout engine object associated with a webbrowser; creating a scripting language object that is native toscripting engine memory space associated with a scripting engine, thescripting language object being associated with the layout engine objectand being accessible through native methods associated with a scriptinglanguage associated with the scripting language object; binding thelayout engine object with the scripting language object via a linkage,wherein the linkage utilizes a custom object that is configured torepresent relationships between objects in the scripting engine memoryspace and objects in layout engine memory space associated with thelayout engine object; redirecting, using the linkage, function callsassociated with the scripting language object to the layout engineobject.
 15. The computer implemented method of claim 14, wherein therelationships comprise parent relationships to parent objects.
 16. Thecomputer implemented method of claim 14, wherein the relationshipscomprise child relationships to child objects.
 17. The computerimplemented method of claim 14, wherein the relationships comprisesibling relationships to sibling objects.
 18. A computer implementedmethod comprising: creating a trampoline that is configured to belogically interposed between a Web browser's scripting engine and anassociated layout engine by: compiling one or more Property DescriptionLanguage (PDL) files that define one or more layout engine programmingobjects and associated APIs and one or more files that define one ormore scripting language objects, and at least one Internet DefinitionLanguage (IDL) file that includes alternate descriptions of at leastsome of the APIs and objects in the PDL files; producing, responsive tosaid compiling, one or more trampoline functions, trampoline anddefinitions, and per type initialization functions configured to enableintegration between the layout engine and the scripting engine, thealternate descriptions including one or more of the followingattributes: one or more annotation/documentation attributes, one or moreglobal object extension attributes, one or more code generationattributes, and one or more API availability attributes; and logicallyinterposing the trampoline between the scripting engine and the layoutengine.
 19. The computer implemented method of claim 18, wherein the atleast one IDL file is configured to include hierarchical relationshipinformation associated with hierarchical arrangements of APIs.
 20. Thecomputer implemented method of claim 18, wherein the one or moreannotation/documentation attributes include one or more of the followingattributes: attributes that can be used for hyper-linking; attributesthat can be used to describe, link, and/or point an interface and/orproperty definition to an associated binary code representation;attributes that can be used to include release information; attributesthat can be used to extend a property with an associated attribute nameand/or Cascading Style Sheet (CSS) property; attributes that can be usedto include testing identification references; or attributes that can beused to include tag identifiers that enable API categorization andsearch-indexing; wherein the one or more global object extensionattributes comprise attributes that can identify one or more interfaceto be grafted as a global object; wherein the one or more codegeneration attributes include one or more of the following attributes:attributes that can be used to control security aspects of a propertyand/or API; attributes that can be used to control defaultinitialization of a property; attributes that can be used to indicateentry points for associated code; and wherein the one or more APIavailability attributes include one or more of the following attributes:attributes that can be used to enable one or more APIs to be availableto a webpage running a first markup language, but unavailable to awebpage running a second different markup language; or an attribute thatcan be used to mark an API as deprecated.